1. Field of the Invention
The present invention is related generally to interactive presentation systems using a display computer, a computer-controlled image projector and a projection screen, and in particular to an interactive display system in which computer control is accomplished by using a wireless optical pointer to project an encoded control cursor onto the projection screen. The projected images are monitored by a video camera, and the control cursor is scanned, detected and decoded for initiating various keyboard commands and/or pointing device (mouse, touch pad, track ball) position-dependent cursor operations.
2. Description of the Related Art
Interactive image projection and display systems use technologies including ultrasonic, infrared and radio frequency (RF) techniques to provide increased user mobility relative to the computer processor and/or display screen. These technologies typically employ a transmitter and receiver to communicate control and status information between the operator and the computer. Display systems have been developed for remotely initiating various computer keyboard commands and/or pointing device (mouse, touch pad, track ball) position-dependent cursor operations, e.g., select, move, left click, right click and double click.
Conventional display systems use sensors positioned on the operator or on the computer, and/or on a display screen to detect movement of the user and/or a wireless pointing device relative to the sensors. While generally acceptable for some applications, these techniques may be subject to proximity or distance limitations. Likewise, these systems require complex and often expensive equipment that may not be readily adaptable to different facilities and may not meet the specific needs of large as well as small viewing audiences.
Portable laptop and notebook computers are now being used for graphical presentations and/or demonstrations, and large display screens are used for slide show presentations and computer generated images to large audiences. Many presentations, such as slide shows and the like, require relatively simple control of the computer during presentation. Commands that advance or reverse slides or initiate a display sequence require only a basic user interface or remote control to communicate with the computer.
More sophisticated presentations, for example computer generated web images containing browser-searchable on-line content, require a complex remote controller interface to effectively operate the computer and position the cursor on the presentation screen for browser control. At the display computer, either the presenter or an assistant controls the projected image by means of key strokes or pointing device (mouse, touch pad, track ball) manipulations to produce position-dependent cursor operations that position a cursor in the appropriate area of the computer monitor display screen, thus exercising control over content selection.
Improvements have been proposed in which an external control cursor is projected by an optical pointer and displayed on the presentation screen. The control cursor is monitored by a remote video camera, and an attribute of the control cursor, e.g., pattern, color, or pixel area size, is decoded and used to emulate a particular keyboard or pointing device operation for input as a command signal to the computer. One limitation of this arrangement is the difficulty in reliably differentiating and detecting the control cursor relative to background images, graphical content and objects projected onto the presentation screen.
Another limitation is that the shape or profile of the projected image of the control cursor may not be reproduced faithfully on the presentation screen unless the optical viewing axis of the monitoring camera and the projection axis of the optical pointer are in alignment. The positioning of the video camera and the optical pointer to provide ideal projection and monitoring angles is unlikely to occur in practice, since the projection orientation of the hand-held pointer will be constantly changing as the presenter moves about, resulting in distortion of the image shape and pixel area size.
There is a continuing interest in providing a system for remotely controlling the computer of an interactive image projection display system that will simplify command and control, while providing reliable execution of remote commands while using an optical pointer at various projection angles, especially in connection with the selection and display of rich content browser images, while giving the presenter improved mobility, thus allowing the presenter to focus his attention on the presentation while minimizing the actions needed to exercise control over content selection and computer operation.